Resolve "Ignore end_time when generating automatic payload"

What does this MR do?

This fixes a bug where an alert that does not provide an explicit fingerprint param could not be auto resolved. end_time was introduced in !41648 (merged).

When a fingerprint isn't explicitly given, providing the end_time generates a new Alert, since aren't excluding the end_time from the payload when generating the fingerprint.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

#250264 (closed)